Electron Transfer Control in Soluble Methane Monooxygenase
Author(s)Wang, Weixue; Iacob, Roxana E.; Luoh, Rebecca P.; Engen, John R.; Lippard, Stephen J.
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The hydroxylation or epoxidation of hydrocarbons by bacterial multicomponent monooxygenases (BMMs) requires the interplay of three or four protein components. How component protein interactions control catalysis, however, is not well understood. In particular, the binding sites of the reductase components on the surface of their cognate hydroxylases and the role(s) that the regulatory proteins play during intermolecular electron transfer leading to the hydroxylase reduction have been enigmatic. Here we determine the reductase binding site on the hydroxylase of a BMM enzyme, soluble methane monooxygenase (sMMO) from Methylococcus capsulatus (Bath). We present evidence that the ferredoxin domain of the reductase binds to the canyon region of the hydroxylase, previously determined to be the regulatory protein binding site as well. The latter thus inhibits reductase binding to the hydroxylase and, consequently, intermolecular electron transfer from the reductase to the hydroxylase diiron active site. The binding competition between the regulatory protein and the reductase may serve as a control mechanism for regulating electron transfer, and other BMM enzymes are likely to adopt the same mechanism.
DepartmentMassachusetts Institute of Technology. Department of Biological Engineering; Massachusetts Institute of Technology. Department of Chemistry
Journal of the American Chemical Society
American Chemical Society (ACS)
Wang, Weixue, Roxana E. Iacob, Rebecca P. Luoh, John R. Engen, and Stephen J. Lippard. “Electron Transfer Control in Soluble Methane Monooxygenase.” Journal of the American Chemical Society 136, no. 27 (July 9, 2014): 9754–62. © 2014 American Chemical Society
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